


by mutual arrangement

by talimpest



Category: Supergirl (TV 2015)
Genre: ABO, Alpha/Beta/Omega Dynamics, F/F
Language: English
Status: Completed
Published: 2018-06-30
Updated: 2018-06-30
Packaged: 2019-05-31 08:28:41
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,892
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15115625
Author URL: https://archiveofourown.org/users/talimpest/pseuds/talimpest
Summary: Ever since Lena presented as an Omega, Kara has been helping her through her heats, but seems strangely shy to let Lena do the same for her in return. Lena has a plan to change that.(Porn, with some plot and a surfeit of emotions.)





	by mutual arrangement

In the towering building of LCorp’s headquarters in the heart of National City, it seems like a usual Friday night. As usual, so late in the night, all the lights are off, except in the topmost office, where Lena Luthor is still at her desk, typing away into a document. She only looks up when a familiar thud sounds from the balcony, and an equally familiar figure walks in through the glass doors.

“Kara!” Lena says, walking forward to greet the woman, her voice coming out a little higher than usual, when she thinks of what she has planned.

Kara’s face, that had seemed a little tired as she had walked in, brightens up as soon as their eyes meet, and she quickens her pace to envelop Lena in their usual hug of greeting.

“Hey.” she says. “I saw the light on, so I thought I’d say goodnight before heading home.”

Lena nods, not that she had needed the explanation. Kara dropping by LCorp to bid her goodnight is practically a nightly ritual with them, by now. She takes another quick look around the office, before turning back to Kara, although it’s still empty, just as it had been an hour before, and the hour before that. With Jess having the night off, and even security having clocked out, the only other soul in the building is the woman in front of her.

It really is just them, Lena realizes with a thrill, as Kara looks at her her with a faint smile.

“Nice job with that raccoon on the news today, Supergirl.” she says, a little teasingly. “How did it even scale that far up the Catco building?”

Kara simply laughs, rolling her eyes upwards in memory of the rodent that had monopolized the news cycle all day, simply by climbing to a precipitous height atop the tallest building in National City, unleashing a social media frenzy until Supergirl had swooped in and brought it back to the ground. Which had, of course, unleashed yet another social media frenzy.

“I’d say nice job back, but you work too hard.” she says instead. “You need to get a little more sleep, Lena.”

She walks over, frowning at the glowing display of Lena’s laptop, open to a new set of acquisition files for a pharma company.

“Don’t tell me you’re going to spend all night on these.” Kara says. “Lena, seriously.”

The worry is a familiar refrain from her, and one that Lena finds secretly touching everytime Kara exhibits it, although she usually blows off the concern. This time, she simply shakes her head, before scanning the office once more, just in case.

“Actually, I was thinking of heading home early for once, tonight.” She says. “With you, Kara. The usual place?”

Kara tilts her head in an adorable display of confusion.

“Our arrangement?” Lena prompts her, and watches with satisfaction, as red suffuses Kara’s cheeks at the mere word.

Her “arrangement” with Kara had started six months ago, shortly after Supergirl had defeated Rhea and put an end to the Daxamite invasion. When all the remaining Daxamites had fled Earth’s lead-infested atmosphere, humanity had breathed a collective sigh of relief. The terror, it seemed, was over at long last.

The Daxamites, though, turned out to have one last trick up their sleeve. Their fleeing ships had fired one last bioattack back on National City, one that took days even to manifest. When it did, it altered the very genetic code of humans, throwing the entire city into chaos. The humans had no idea what had happened to them, until Supergirl - who knew of such attacks due to the frequent warfare between Krypton and Daxam - swooped in to explain. Appearing on panels with scientific experts on every major news channel in National City, she had explained about “alphas” and “betas” and “omegas” until even Lena’s head had begun to spun.

“But your heat cycle isn’t-” Kara now starts, before looking concerned. “Did something trigger it earlier?”

Lena shakes her head, breathing in deeply as Kara’s safe and warm scent washes over her.

“No.” she murmurs. “The way you take care of me keeps it in good control, Kara.”

The resulting genetic changes of the bioattack had thrown the human population of National City into chaos, until a tentative new balance was found, as people began to adapt to this invasive change to the very autonomy of their bodies. For Lena Luthor, however, it was not so easy as for most others.

Due to the unique circumstances of her life, the change was more drastic to Lena than most. When the chaos had settled, she had found out that she had presented as an omega, and that her body was bound to go into heat, again and again in a vicious cycle. This was terrifying for her, who had no safety net of a family to turn to, and no one else who could help her with something like this. No employees, not even Jess, could be trusted to keep quiet on something like this. When the heat took hold of her, she would have no one to turn to, no one to help her through it, no one to make sure that she didn’t make a fool out of herself by throwing herself at the first alpha that crossed her path.

As far as bioweapons went, Lena had to admit, the Daxamites’ parting attack was cruelly and unusually efficient.

To add insult to injury, she knew that some of the misogynistic pigs that she had to work alongside would have something to say about the fact that she, the CEO, had presented as an omega. Inevitable, some of them - Morgan Edge, for instance - would draw some nonsensical negative link between that and her competency, and more than a few idiots in the industry would listen to him. L Corp would suffer as a result, and that seemed worse to Lena than any injury to her own reputation.

And so, she had reached out to the only person in National City who might have some way of helping her. Who _had_ helped her.

“I’m not talking about me, Kara.” Lena now says, quietly, fixing her eyes on Kara and willing herself to go through with this. “I’m talking about you.”

She can see the exact moment her words register, as Kara’s cheeks grow redder, and her eyes widen, while her nose flares.

“Your rut.” Lena says, stalking closer to the plainclothes-clad superhero. “It’s about time for it, right? Give or take a couple days?”

She remembers the day she had finally called her for help, and Kara had strode in, in full Supergirl regalia, her face pinched with the stress of dealing with the chaos that the bioattack had caused in the city. She had then laid another bombshell on Lena. The Kryptonians, used to such biological warfare with the Daxamites, had bioengineered suppressants long ago, that would help keep their heats and ruts in check. They were only effective on Kryptonian physiologies, though, and absolutely useless to humans. It was clear that Lena would likely have to suffer through at least a few cycles of heat, before a suppressant that worked on humans could be manufactured.

Now, as Lena moves closer, Kara steps back as if reflexively, and she seems to be holding her breath, as if simply breathing in Lena’s scent is too much.

“I’ll take suppressants as usual.” Kara says. “It’s fine Lena, you don’t have to-”

Lena just steps closer, backing Kara farther into her desk.

“I don’t have to what?” She notices with some glee that if Kara had to retreat any further from her, she’d have to literally break through the desk. “Help you like you helped me?”

Because Kara _had_ helped. Her dilemma had left only one alternative, Kara had offered, stammering her way through that sentence, while biting her lip and staring at Lena nervously. It had taken Lena a moment to understand what she was proposing. She was proposing that someone should take care of Lena during the heats, someone who would keep her sated and safe, someone who would do all this without blurting out the details to the press at the first available opportunity.

It had taken a few more moments of watching Kara’s flushed face, and listening to her nervous stammers, for Lena to understand that Kara wasn’t talking about someone in the abstract. She was talking about _herself._

And it had made sense, instantly. Kara had trusted Lena with her secret identity almost immediately after the Daxamite invasion. More importantly, she had trusted Lena with stories of her dying planet, with details of her growing disillusionment with her dead parents, and with the tragedy of her dead aunt. And now, she was asking Lena to trust her in return.

It had been an easier choice than breathing.

“Take care of me.” Lena had said, putting her heart on her sleeve, and holding it out to the woman who had fallen to Earth from another world.

And oh, Kara _had_ taken care of her. Her deft fingers had quickly learnt exactly how Lena liked it, stroking her to climax after climax, while Lena writhed under her, gasping in the throes of her heat. Kara had even, after much initial blushing and stammering, gone down on her, that dexterous tongue taking Lena apart even more quickly than her fingers. She had whispered the right words into Lena’s ears, sometimes gentle and sometimes filthy, had kissed her softly as Lena had come down from her high, and even held her afterwards, until Lena fell asleep on to wake in the flare of another heat. At which point, of course, Kara had taken care of her again.

And, she had never breathed a word of their arrangement to a single soul. No tabloid had been published with Lena’s face plastered on the front page and SUPERGIRL’S SORDID SEX SCANDAL splashed in bold type under it. No press conference had been called by Morgan Edge about her omega status.

On the whole, Lena has to admit, the arrangement had turned out entirely satisfactory.

For her, that is.

Now, Kara‘s eyes go dark as she approaches closer, the blue and black blending into a brilliant, enchanting shade.

“Lena, stop.” she says, her voice serious now. “You don’t know what you’re starting.”

There’s a slight growl to her voice that has Lena’s thighs clenching automatically, that makes her almost lick her lips in anticipation. Oh yes, her alpha wants her.

Lena just has to convince her that it is mutual.

“You’ve been so good to me through my heats.” she says, her voice a little raspy herself, as she remembers Kara’s gentle touch, remembers how her fingers had stroked the unbearable heat inside Lena into dizzying heights of ecstasy. “I’m just offering to do the same for you.”

Because that was the point that Lena had found herself worrying over, and feeling guilty about, as the arrangement continued.

Yes, Kara took care of her, but what about Kara? The suppressants could keep her alpha urges under control, but it couldn’t be easy to always have to hold back a part of yourself. Kara had always had to hide, and to lock away so many parts of herself, Lena knew. It had struck her as supremely unfair, then, that she had to hold herself back even in such a very private, intimate matter as sex.

And then, of course, there was the part of Lena that had wanted to experience for herself, what it would be like to be with Kara, to really be with her. That had wanted Kara inside her, wanted the pleasure of seeing the Kryptonian untethered. It had made her shiver just to think about it, to imagine her and Kara, intertwined in bed, letting go together. It wasn’t that Lena thought there was something magical about penetrative sex with an alpha, that was going to be so much better than everything else Kara had done to her previously. She was more bothered by the fact that Kara had clearly been holding her own desires back during those times, and focused entirely on giving Lena pleasure, than on sharing the moment with her.

And that was on both of them, Lena had decided. Of course that had been the original agreement, for Kara to take care of her during her heats. She had never thought it through, unfamiliar with the whole thing as she was, and of course Kara wouldn’t force herself on her. Not that Lena would have minded in the slightest, but she knew Kara, knew that Kara carried her power like a great burden and responsibility. It would be exactly like Kara to conclude that ignoring her own wants and needs was the right way to go about things.

Except that it was, of course, not the right way. Things needed to change.

And change, Lena decides now, taking an inspirational quote and applying it to a context that its originator probably never dreamed it would be used in, starts with her.

To underscore her own point, she reaches a hand down, and strokes at the front of Kara’s slacks, softly but with clear intent. Kara yelps at the first contact, and Lena has to fight to keep her smile from becoming too fierce, too smug. She keeps her movements gentle and light, more to give Kara an idea of what she has in mind, than to initiate any heavy petting right then and there. There’s a definite bulge there, as she rubs, and Kara’s breathing is getting noticeably shallower, her nostrils flaring again.

“Kara,” Lena murmurs, “don’t you want this?”

For a moment, for one breath-taking moment, Kara’s fingers fist into the clothing around Lena’s arms, and she clutches her tight, before she draws a shaky breath, and her grip loosens.

“I just,” she mumbles, “You told me how much you hated all the guys that Lillian tried to set you up with. I don’t wanna be like that.”

And Lena wants to cry because how could Kara, careful Kara who sometime touches her as if she were glass, would ever think of herself like that, like those men who had wanted to take and take and take. So, she just draws Kara in, holding her tight and nestling against the curve of her neck, while her hands move up to cradle Kara’s shoulders.

“I just want to make you feel good.” Lena tells her, inhaling the soft scent of her in. “Like the way you make me feel, Kara.”

“If you keep doing this, it’s definitely going to trigger my rut.” Kara tells her, her eyes earnest, and doubtful at once. “Lena, i don’t want to force you into anything.”

In response, Lena just smiles, and presses into her tighter, shifting so that the now-clear bulge between Kara’s thighs is pressing between her own legs, a delicious promise of what is to come. Kara gasps at the contact.

“You’re only a few hours away from your cycle, anyways.” Lena murmurs. “Forget the suppressants, just take me home.”

“ _Rao_ , Lena.” Kara says, her voice throaty and low, and Lena almost shivers, because with that voice? Kara can take her anywhere, could shout from the top of the LCorp building that she’s fucking Lena Luthor, and Lena would be okay with it right now.

“Take me home, alpha.” she repeats, burying her head into Kara’s shoulders, and wrapping her arms around her waist, already thrumming with anticipation.

There’s a sharp intake of breath from Kara at that, and then they’re at her apartment in a matter of seconds, Kara flying them in through the window without a moment’s delay, and depositing Lena in her living room sofa with a gentleness that belies the speed at which she’d flown them there.

Once they’re there, though, Kara seems at a loss for what to do, by the way she paces up and down the length of the living room, before peering towards the kitchen, then the window, then another window, then back at the kitchen again, all in a flurry of nervous energy.

“Wow, I am hungry!” she says, her voice rushed. “I guess I better order us something, huh? I bet you’re starving too. Jess tells me you keep working through lunch. That’s not really healthy, you know. If I worked through lunch, I think I’d be-”

She seems to be babbling, looking anywhere but at Lena.  

“Kara.” Lena says.

Kara freezes, but she’s still looking at the wall, the fridge, the floor, while Lena stalks closer.

“Look at me, Kara.” Lena says, with soft insistence, tugging her closer by hooking two fingers into the front beltloops of her pants.

Kara follows her slight pull as if one hypnotized, her throat working visibly as they finally lock gazes.

“I’ve never trusted anyone as easily as I trust you.” Lena says, not moving her hands away. “That’s why I could only accept you, to take care of my in my heats. You’ve always been so good to me.”

With hands that shake only a little, she undoes the belt buckle, maintaining eye contact with Kara all the while, as the metal clasp comes undone.

“Your touch is so wonderful.” she says. “So careful, always figuring out what I want. Why would you think I wouldn’t want that, or you?”

She tosses the belt away, before thumbing over the zipper of her pants, pausing a moment for Kara to catch on.

“What are you doing?” Kara says, her voice low and breathy. “Lena, what...oh. _Oh.”_

Her voice drops to a rough whisper at the last part, when Lena unzips her slacks, pulls them down partway, and then kneels down in front of her.

“Just so you know,” she says, looking up at Kara. “I’ve never done this before. Not to the guys my mother set me up with, not to girls, not to anyone.”

Kara just looks down at her, breathing hard, her eyes wide and worshipful and reverent.

“I trust you.” Lena says. “That’s why I feel safe, doing things like... this, with you.”

Kara nods after a visible swallow, and her hands come to rest on Lena’s head, as she bends down. The touch is feather light, Kara’s trembling fingers running through her hair as if she’s shivering from the sheer pressure of controlling herself. The trembling only gets more noticeable, as Lena’s tongue meets her cock, and licks up the length of it, again and again in a steady rhythm.

“Oh.” Kara chokes out, the exclamation stifled and rough. “ _Rao_ , Lena.”

Lena keeps up the steady strokes of her tongue, feeling Kara stiffen and grow impossibly erect under her ministrations. Every atom of her is focused on Kara, on the sounds she makes, on giving her pleasure. Focused, too, on the thought of Kara inside her, taking her apart as only she knows how to do. She’s lost, absolutely lost in Kara’s sighs and groans, when she finally takes the entire girth of the cock into her mouth, and Kara’s grip on her hair is suddenly almost painfully tight.

“Oh, _Rao_ .” Her knees are almost buckling. “Lena, _please_.”

Lena lavishes it with attention, moving up and down, licking, swirling, feeling herself growing wetter with every moan she gets out of Kara, and then-

\- and then, there are insistent hands on her shoulders, pushing her away. Lena looks up, feeling insecure and confused for a moment, until she sees that Kara is staring down at her with wild eyes, looking utterly ruined.

“That’s amazing.” Kara says in a rush. “But Lena, I want to-”

Her voice turns shy then, and soft.

“I want to finish with you.”

Lena blinks and then swallows, getting to her feet. Kara pulls her into a kiss as soon as she’s upright, a soft one, despite how hurried and feverish it feels.

“Take me to bed, then.” Lena says, when they break apart.

There’s another blur and then they’re in the bedroom. Kara sits down on the bed with shaky legs, while Lena chooses to stay standing, still stumbling a little from the abrupt landing. Another look at Kara finds her flushed again, and from the jerky movement of the last flight, Lena knows she’s at the end of her control.

“Is this how the rest of you feel like all the time?” Kara says, her breathing becoming heavier and heavier, “I feel like my entire body is on fire.”

“Good.” Lena says, more than satisfied at a job well done, and then her breath quickens, as a wave of heat washes over her body, almost making her stumble again. “Kara, I’m pretty sure I’m going into sympathetic heat.”

Kara snarls then, and there’s a flurry of movement, as she _rips_ apart her own clothing. Lena licks her lips, but backs away as Kara reaches for her, feeling her lips curve into a smile that might be just a little wicked.

“I can undress myself, alpha.” she says, running a meandering hand over her blouse, before teasing off the first button.

Kara’s lips flare, as if in another silent snarl, but she remains on the bed, naked and watching with ravenous eyes, as Lena slowly undresses for her. Her cock is in plain view, long and still hard from prior attentions, and Lena feels wetness pool between her thighs just looking at it, at Kara. She finally pops the last button and pulls the blouse off, making short work of her skirt and underwear, and enjoying how Kara’s eyes go even darker as she stands before her, equally naked.

Kara draws in another shallow breath when Lena first gets on the bed and crawls towards her. Her cock twitches a little as Lena approaches, but Kara reaches out with her hands instead, running wondering fingers up Lena’s arms, across the curve of her belly, before cradling her breasts and thumbing them softly. Lena sighs, as another hot wave of wants washes over her. Oh, she loves her alpha, her Kara, so soft and gentle even in the midst of what must surely be a  mind-dazing rut.

“ _Rao_ , Lena.” Kara says, her voice a soft growl. “You’re so beautiful.”

Her body is letting off pheromones in waves, making Lena feel almost aflame with want. She doesn’t want Kara to be gentle anymore. She feels like she wants Kara to rip her apart, to give into her urges until they can hear Lena screaming five floors down, until the whole world knows how much Kara Danvers wants Lena Luthor.

“Kara,” she says, hovering over her, so that the alpha lies down, never once breaking eye contact with her. “I know you’re close. And, I consent. I want this as much as you, ok?”

To emphasize her words, she draws down closer to Kara, and kisses her softly, while moving her sex down into her groin, right against her cock. Kara gasps and fists her hands into the sheets of her bed, ripping the fabric into into threads, as if to control herself from lunging for Lena.

“Lena, I can’t hold myself back for much longer.” She says, biting her lips.

And dammit, Lena wants those hands on her _now_ , wants their firm touch sliding away the heat that seems to coruscate her body as she moves against Kara.

“So don’t hold back.” she says, trailing another open-mouthed kiss over swollen lips, before moving down into her again, so that her sex travels along the shaft of Kara’s cock, leaving trails of wetness in its wake. “Who am I, alpha?”

Then Kara snarls, her gaze wild, and Lena finds herself bodily flipped on her back, with Kara staring down at her, eyes as dark as night and breathing coming in shallow puffs.

“Mine.” Kara growls, leaning down to kiss her, bruisingly hard, stealing the breath away from Lena. “You’re _my_ omega. Mine!”

“Yours.” Lena affirms, breathless, when their lips part for air. _Yours. Yours. Yours!_ “Oh god, Kara, yes, I’m yours.”

And then, with a long sure stroke, Kara is inside her, the girth of her settling into Lena’s core like it’s coming home, like they were always meant to be like this, impossibly intertwined with each other.

“Yes!” Lena gasps out, clinging to her body, kissing and biting at every part of Kara that she can reach, the side of her mouth, her jaw, her pulsing neck, “Yes, yes, yes, Kara, _yes._ ”

Kara kisses her back just as feverishly, muttering to her incoherently as she moves inside Lena. And Lena just feels... _filled_ , gloriously filled with a want that is satisfied by each steady stroke of Kara’s cock into her. It’s not long before both their gasped out exclamations turn into wordless moans, as they move against each other, losing themselves in the rhythm of it. Lena has always enjoyed everything Kara had done to her, in her previous heats, but this feels different. She feels lost in the softness of Kara’s body wrapped around her, her already raging want flamed up into something burning by the alpha panting against her ear, just as far gone as her. Kara taking care of her in their previous trysts had been amazing, but it’s different now, _more,_ because she’s not holding herself back, she’s as lost in the moment as Lena.

She should have asked Kara to do this sooner. Lena’s mind latches onto that coherent thought, in its lust-dazed wandering. They could have been doing this so much sooner.

As they move against each other, a new and unfamiliar pressure thrusts against Lena’s opening. She swallows as she realizes it’s the base of Kara’s cock growing, feels the swell of it pressing against her, as Kara slows down her movements, obviously realizing that she’s going to knot.

“It’s ok, keep going.” Lena murmurs against her mouth, kissing her again and again when Kara mumbles something uncertainly. “I want you, Kara. All of you.”

She moves up into Kara as she speaks, taking the base of the knot in. Kara seems satisfied with that, moaning more hushed and undecipherable words against Lena’s mouth, before moving into her faster. Lena moves with her as she strokes in and out, taking a little more of the knot in each time. The pressure is tight, and a little painful, in a dizzyingly pleasurable way that has her almost blacking out from the sheer assault of sensations.

“ _Rao_ , Lena.” Kara gasps out, as her knot goes in all the way.

There’s a momentary flare of pain, and then all Lena feels is tightness, of security, with Kara’s cock buried fully inside her, the knot throbbing deliciously against the walls of her sex. She almost blacks out again, from the new wave of pleasure that overtakes her, and she can hear Kara voicing her name repeatedly, as she comes inside Lena in powerful crests. Lena shudders with the force of the release inside her, unable to do more than mewl and wrap herself even tighter around Kara, while their mutual orgasm washes over them.

When she comes to herself again, Kara is still buried inside her, breathing roughly and staring down at her.

“I won’t be able to get out for a while.” Kara says, biting her lips and looking uncertain. “And even then-”

“I know.” Lena says, shifting a little, and feeling the wonderful throb of the knot inside her. “I know what I signed up for, Kara. I know your rut is triggered, too. I already switched around my schedule for the next few days, and Jess knows how to keep things running by now. I’m here, for as long as you’ll need me.”

"You’re wonderful.” Kara says, looking down at her reverently. “How did I get so lucky?”

“I’m the lucky one.” Lena corrects her, shifting up to place another slow kiss against Kara’s mouth. Kara sighs and returns it, and Lena feels more content than she has in ages.

Then, there’s a loud grumble, as Kara’s stomach protests its hungriness very loudly, and Lena pulls back, more than a little amused, to stare into the wide eyes of a very mortified alpha.

“Oops.” says Kara, embarrassedly. “I, uh, might have worked through lunch, too.”

Lena just shakes her head in amusement, before inclining her head over at the pile of takeout menus that had accumulated on her bedside table, courtesy of Kara herself from their previous post-coital snugglings.

“So... pizza later on?” Kara asks, looking hopeful.

“Okay, pizza later.” Lena confirms, with a quiet laugh as she sinks deeper into the bed, and Kara flops down on top of her. “But, we’re definitely not skipping the veggies this time.”

Kara makes a half-hearted protest, and Lena just smiles again. She feels sated, but also knows the feeling is temporary, knows that she’ll be ready again in a few hours, to meet Kara’s rut as it flares up. Right now, though, she just feels loved and secure, away from disapproving mothers and disappointed brothers, safe in the arms of an alpha who looks at her with so much wonder and reverence that it takes her breath away.

Oh yes, she thinks, as she drifts off to sleep to the rhythm of Kara’s regular breathing, they should have been doing this ages ago. But, at least she’ll make sure they’ll keep doing it.

xxx


End file.
